Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2015

Asset Retirement Obligation Disclosure [Abstract]

Reconciliation of Asset Retirement Obligations which are Included in Other Liabilities

The following table reconciles our AROs as of the dates presented, which are included in the Other liabilities caption on our Consolidated Balance Sheets: 

	As of December 31,
	2015			2014
Balance at beginning of year	$	5,890		$	6,437
Changes in estimates	172			112
Liabilities incurred	110			238
Liabilities settled	—			(92		)
Sale of properties	(3,932		)	(1,224		)
Accretion expense	381			419
Balance at end of year	$	2,621		$	5,890